A new study has found that summers in the arctic are getting longer, thinning the ice that polar bears use to hunt the seals that they eat.
A different study showed ice there has thinned by 40% in the last 40 years.
The problem may make global warming worse because ice reflects sunlight away from the earth, and without the ice it may stay here and get warmer.
The study has figured out that summers in the arctic are getting longer, and that's linked to the thinning ice.
But other scientists say the things are not so bad.
They think the amount of ice there is the same, it's just moved north where the satellite used for the study can't see it.
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